Hi all! I am fairly new (less then a year) to all this and own a Shapeoko XXL. I have been going along and everything seems fine. However, this past weekend I started a project that has some fairly tight tolerances, an award plaque with lettering near the edge. I ran it and noticed that the lettering was going too far. So I scrapped it and tried again. This time I made sure the material was the exact dimensions, 11.25 inches, but when I manually jog the machine from zero up the y axis 11.25 inches, it goes off the material about .1 inch.
I thought that was weird so I tried the circle/diamond/square test to see how calibrated the machine was and it turned out great.
Square-3.99 inches and was supposed to be 4 inches
Diamond- 2.49 inches and was supposed to be 2.5 inches
Circle- 2 inches exactly